Be sent up to bed having gone into a decline (5)
I believe the answer is:
ebbed
'gone into a decline' is the definition.
I can't judge whether this definition defines the answer.
'be sent up to bed' is the wordplay.
'sent up' says the letters should be written in reverse.
'to' is a charade indicator (letters next to each other).
'be' written backwards gives 'eb'.
'eb'+'bed'='EBBED'
'having' acts as a link.
Can you help me to learn more?
(Other definitions for ebbed that I've seen before include "Flowed back or receded" , "Diminished" , "Went out like tide" .)